"Unrecognized as command" message when trying to call Java program from command line

I am unable to call my java program from the command line. I keep getting this message:

"InitArray is not recognized as an internal or external command, operable program or batch file."

I can read the directory with the 'dir' command and see the program that I am trying to launch but cannot get past this error message!

Here is what I see: C:\Users\myName\Java_WorkSpace> And then I enter: InitArray 5 0 4

Again, I can see this program in the directory but I cannot access it. WHAT AM I DOING WRONG???

Here is the program code:

public class InitArray 
{
public static void main(String[] args)
{
    // check number of command-line arguments
    if ( args.length != 3)
        System.out.println(
    "Error: Please re-enter the entire command, including\n" +
    "an array size, initial value and increment.");
    else
    {
    int arrayLength = Integer.parseInt(args[0]); 
    int[] array = new int[arrayLength];

    int initialValue = Integer.parseInt(args[1]);
    int increment = Integer.parseInt(args[2]);

    // calculate value for each array element
    for ( int counter = 0; counter < array.length; counter++ )
        array[counter] = initialValue + increment * counter;

    System.out.printf("%s%8s\n", "Index", "Value");

    // display array index and value
    for ( int counter = 0; counter < array.length; counter++ )
        System.out.printf("%5d%8d\n", counter, array[counter]);
    } // end else
} // end main
} // end class InitArray